Pipelayer hydraulic drawworks with free-fall

ABSTRACT

In cable winding gear driven by a hydraulic motor of the kind having radial pistons driving a surrounding cam ring, a control is provided for applying differential pressure to the motor pistons so that they are disengaged from the cam ring which can then rotate freely. This provision enables the cable to be run out freely, so that, for example, in a crane free fall of the load can be allowed while avoiding damage to the motor. Pipelaying equipment including the free-fall provision is described.

Matte States Patent [191 Axelsson et a1.

[ PIPELAYER HYDRAULIC DRAWWORKS WITH FREE-FALL [75] Inventors: EvaldGustav Axelsson, Stafford;

David Collier, Brewood, both of England [73] Assignee: CaterpillarTractor Co., Peoria, 111. 221 Filed: on. 29, 1970 [21] Appl. No.: 84,978

[30] Foreign Application Priority Data June 26, 1970 Great Britain31078/70 [52] U.S. Cl. 91/497 [51] Int. Cl. F0lb 13/06 [58] Field ofSearch 91/472, 491; 417/214;

[56] References Cited UNITED STATES PATENTS 2,453,309 11/1948 Douglas418/82 2,789,542 4/1957 Vander Kay 91/48 2,831,554 4/1958 Reynolds254/186 3,036,435 5/1962 Samuely 60/19 3,184,018 5/1965 Christison254/186 3,230,715 l/l966 Klein et a1. 60/53 111 3,815,478 1 June 11,1974 3,244,405 5/1966 Hanning 254/186 3,283,668 1/1965 Louhio 91/443,323,779 6/1967 Burnett 254/186 3,396,666 8/1968 Moochha|a.. 418/823,416,452 12/1968 Misulis 91/473 3,527,144 9/1970 Firth 91/472 3,662,5515/1972 Denker.... 91/501 3,685,290 8/1972 Krusche 60/52 US FOREIGNPATENTS OR APPLICATIONS 1,004,080 12/1962 Great Britain 417/214 PrimaryExaminerWi1liam L. Freeh Attorney, Agent, or Firm-Phillips, Moore,Weissenberger, Lempio & Strabala [5 7] ABSTRACT In cable winding geardriven by a hydraulic motor of the kind having radial pistons driving asurrounding cam ring, a control is provided for applying differentialpressure to the motor pistons so that they are disengaged from the camring which can then rotate freely. This provision enables the cable tobe run out freely, so that, for example, in a crane free fall of theload can be allowed while avoiding damage to the m0- tor. Pipe-layingequipment including the free-fall provision is described.

I 13 Claims, 4 Drawing Figures PATENTEHJHM 1 197 3.815478 SHEET 3 [IF 343 48 A a 46+ r 75 a Eg 4 PIPELAYER HYDRAULIC DRAWWORKS WITH FREE-FALLThis invention is concerned with improvements in or relating to systemsfor operating and controlling winches, hoists, windlasses or the likewhich are driven by hydraulic motors.

In particular, this invention is concerned with systems embodying ahydraulic motor of the kind including a stationary cylinder having anumber of radial bores in each of which a piston is displaceable, and acam ring which is rotatably driven by the pistons. The cam faces of thecam ring are engaged by driving means. such as rollers mounted on theradially outward ends of the pistons, or the outer end faces of thepistons, and hydraulic fluid is selectively supplied to the bores toradially displace the pistons in a predetermined sequence whereby thepressure engagement of the driving means with the cam faces rotates thecam ring from which the drive is obtained in any suitable manner. Suchhydraulic motors as above described are herein referred to as of thekind specified.

Hydraulic motors of the kind specified are already well known and theyare used for driving winches, hoists, windlasses or the like. Althoughin such applications hydraulic motors of the kind specified are verysatisfactory, it is most desirable to be able to operate the winch orthe like in the conventional manner in which the drive can be disengagedso as to allow the winch drum or the like to rotate freely or over-runthe drive. For example, it is desirable to provide an operatingcondition such that the load supported by the winch can fall freelyunder gravity, or such that the cable or drag line can run out freely.

in systems having a mechanical drive transmission this drive-freecondition can easily be achieved by a releasible clutch arrangement.However, with a hydraulic motor of the kind specified direct drive tothe winch or the like is utilised. We have found that in a hydraulicsystem where the source of hydraulic fluid for the motor is derivedsolely from one or more pumps, and not a pressure accumulator,free-rotation of the cam ring cannot be obtained without risk ofdamaging the hydraulic motor. The reason for this is that in a hydraulicmotor of the kind specified the flow of hydraulic fluid is arranged sothat the pistons are urged radially outward whereby the driving meansare maintained in engagement with the cam faces. Even if the supply ofhydraulic fluid to the bores is interrupted or reduced, then at leastsome of the pistons will fall radially outwardly of their bores due togravity so that at least some of the driving means engage with the camfaces. Accordingly, when the cam ring is not being driven by the drivingmeans, but is rotated by the torque applied by the load on the winchcable or the like, the uncontrolled engagement of the driving means withthe cam faces of the rotating cam ring causes excessive damage to themotor; in certain instances the cam faces are damaged, or the motorbearing may crack or break up.

It is an object of this invention to provide in a system for operatingand controlling a winch hoist or the like driven by a hydraulic motor ofthe kind specified, an improvement whereby such free fall of the load,or free-running out of the load cable can be achieved without theaforementioned risk of damage to the hydraulic motor.

Further objects of this invention are to provide an improved hydraulicsystem for operating and controlling a winch, hoist or the like drivenby a hydraulic motor of the kind specified, and to provide a winch,hoist or the like operated and controlled by such improved hydraulicsystem.

Other objectives will be apparent from the description of preferredembodiment of this invention given later herein.

According to the broadest aspect of this invention, we provide in asystem for operating and controlling winding gear, such as a winch,hoist, Windlass or the like, driven by a hydraulic motor of the kindspecified and to which hydraulic fluid is supplied by pump means, theimprovement of valve means for controlling the flow of hydraulic fluidand which valve means on actuation is arranged to produce in thehydraulic motor a hydraulic pressure differential acting on the pistonsto displace them radially inwards to an extent such that the drivingmeans are maintained out of contact with the cam faces of the cam ringwhich can then rotate freely.

In theory there are probably many ways in which such hydraulic pressuredifferential may be developed by controlling the flow of hydraulic fluidthrough valve means. However, practical considerations are of paramountimportance because of problems that may arise such as, the adaptabilityof the hydraulic motor, the overheating of the hydraulic fluid, themaximum flow capacity of the pump means, and the overall complexity andcost of providing a special valve arrangement. We believe that we havedevised a most practical system which avoids the kinds of problemsaforementioned.

One of the preferred ways of obtaining the hydraulic pressuredifferential in the hydraulic motor is to arrange for the valve means toreduce hydraulic pressure in the cylinder bores and to maintain a lowhydraulic pressure in the motor casing so as to develop a pressuredifferential sufficient to displace the pistons radially inwards. Inthis manner a relativey low hydraulic pressure in the motor casing canbe utilised to displace the pistons,and when the drive is to berestored, hydraulic fluid can be supplied to the cylinder to re-engagethe driving means with the cam ring, and then hydraulic fluid fordriving the motor may be supplied at the required flow rate.

Although it is envisaged within the scope of this invention to arrangefor the valve means merely to control the flow of hydraulic fluid intothe motor casing so as to develop therein a hydraulic pressure acting onthe radially outer parts of the pistons greater than the hydraulicpressure in the cylinder bores as applied to the radially inner parts ofthe pistons, this has the disadvantage that the motor casing, includingthe cam ring will have to be designed to withstand very high burstingloads due to the high hydraulic pressures involved. Additionally, theflow capacity of the pump means and overheating of the hydraulic fluidmay lead to further problems. Usually a hydraulic motor of the kindspecified is designed to operate with no or very low hydraulic pressurein the motor casing, and thus where it is desired merely to apply ourinvention to existing hydraulic motors of the kind specified theaforementioned preferred way of developing the hydraulic pressuredifferential can most conveniently be adopted.

Of course the valve means has to be arranged to act, on actuation. inconcert with the other essential operational controls of the winch orthe like which must be maintained either inoperative or functional, forinstance when the load is released the winch brake must be held off.However, these considerata will be fully understood from an embodimentof the invention which is described later herein.

This invention is also deemed to include a winch,

hoist. windlass or the like operated and controlled by a hydraulicsystem, embodying our improvement as well as the hydraulic system perse.

One application of this invention is in a hydraulic systern foroperating and controlling pipe-laying apparatus adapted for attachmentto, or incorporation in a tractor, preferably of the tracked type.

By way of example an embodiment of this application of this inventionwill now be described with reference to the accompanying drawings inwhich:

FIG. 1 is a front-elevation of pipe-laying apparatus according to theinvention mounted on a tractor;

FIG. 2V is a diagrammatic view of a hydraulic motor of thekindvspecifled;

FIG. 3 is aidiagram of the hydraulic operation and control system forthe boom of the pipe-laying apparatus of FIG. I and;

FIG'. 4' is a diagram of the hydraulic operation and control system forcounterweights and a hoist of the pipe-laying-apparatus.

The principal components of the pipe-laying apparatus which are mountedon the tractor comprise a saddle l on one side of which are carried aset of hydraulically controlled counterweights 2 and two winches 3 eachadapted to be driven by a hydraulic motor of the kind specified and ofwhich further details will be given later. On the other side of thesaddle is mounted the boom 4 which is raised and lowered by one of thewinches 3, and the other end of the boom carries the hoist 5 which israised and lowered by the other winch 3. The hoist 5 and boom 4 can beoperated independently or simultaneously.

The hydraulic motors driving the winches 3 are each of the kind shown inFIG. 2 and including a stationary cylinder block6 having a number ofradial bores in each of which a piston 7 is displaceable, and a cam ring8 which is rotatably driven by the pistons. The cam faces of the camring 8 are engaged by driving means, such as rollers 9 mounted on theradially outward ends of the pistons, or the outer end faces of thepistons, and hydraulic'fluid is selectively supplied to the bores todisplace the pistons 7 radially in a predetermined sequence whereby thepressure engagement of the driving means with the cam faces rotates thecam ring from which the drive is obtained in any suitable manner.

The hydraulic system depicted in FIGS. 3 and 4 is for operating andcontrolling the foregoing apparatus and its ancillary parts. The poweris derived from. the tractor engine independently of drive transmission,and it is arranged to drive the fixed displacement hydraulic pumps whichsupply hydraulic fluid to the three parts of the hydraulic system foractuating:

i. the boom 4;

ii. the counter-weights 2; and

iii. the hoist 5.

Each of these three parts of the system will now be described withreference to FIGS. 3 and 4 which are in the form of circuit diagramswith all the control valves shown in the neutral position. i. The BoomSystem A fixed displacement hydraulic pump 10 driven from the enginedraws hydraulic fluid through a suction filter 12 from an open or lowpressure reservoir II. Hydraulic fluid supply from the output line 13 ofthe pump [0 is controlled by a three position open-centre valve 14 whichis shown in the neutral position. By means ofthe valve 14 hydraulicfluid may be supplied to a reversible hydraulic motor 15 of the kindspecified which is connected directly tothe winch drum, and thehydraulic fluid may be returned to the reservoir 11.

For raising the boom 4, the valve 14 is displaced to a second position,which corresponds to moving it to the extreme right in the accompanyingdrawing. In this second position the motor 15 is rotated in one sense byhydraulic fluid supplied through line 16 to the motor 15 and dischargedthrough the line 17 through the valve 14, to line 18 returning to thereservoir 11. Hydraulic fluid is also drained from the motor casingthrough line 19 back to the reservoir 11.

Associated with line 16 is a valve 20 which is normally closed, butwhich on actuation serves to connect the line 16 with line 21 leading tothe reservoir 11. The valve 20 is actuated by the engagement of a springloaded abutment 22 which is arranged to be engaged by the boom if hisraised to an over-centre position, or other predetermined attitude ofelevation in relation to the tractor. As will be appreciated, on suchactuation of the valve 20, the supply of hydraulic fluid through line 16to the motor 15 is prevented as the line 16 is connected through valve20 to the reservoir return line 2l,.and further elevation of the boom isprevented. For lowering the boom, the motor 15 is rotated in theopposite sense by changing the direction of flow of the hydraulic fluidsupplied to the motor 15. This is achieved by displacing the valve I4 toa third position. corresponding to the extreme left in the accompanyingdrawing. In this third position, hydraulic fluid is supplied to themotor 15 from the pump output line 13 through line 17 and dischargedthrough line 16, through valves 14 to line 18 which is connected to thereservoir 11.

In order to maintain the boom at a particular attitude, the motor 15 isprovided with a counterbalance valve arrangement as depicted in therectangular out-- line referenced 23. This counterbalance valvearrangement is adapted only to open when a predetermined high pressureis exceeded so that the motor can operate with full back pressure.

The boom winch is provided with a conventional spring operated bandbrake that is arranged to be held in the off" position by a hydraulicbrake cylinder 25 which is connected to the valve 14 by a line 26.Hydraulic pressure is maintained in the brake cylinder 25 whilst themotor 15 is driven in either sense. When no hydraulic fluid is suppliedto the motor 15, namely when valve 14 is in the neutral position asdepicted, the brake line 26 is open to the reservoir return line 18 andthe hydraulic cylinder 25 is released so that the brake is applied.Additionally, if there should be a loss of hydraulic fluid withconsequent reduction in pressure in any of the supply linesaforementioned the brake is automatically applied.

By way of further explanation of the boom system of FIG. 3, the controlvalve 14, when in the neutral position shown, blocks lines 16 and 17from lines 13 and 18 and communicates flow from pump totank 11 viaconduits l3 and 18. In this condition, the brake 25 is in communicationwith the tank via the conduit 26 which is a branch of conduit 13. Brake25, which is normally applied by spring force, is allowed to be appliedto restrict movement of the boom. Release of the brake is accomplishedby pressurization of the brake cylinder to overcome the spring bias whendesired.

In order to lower the boom, the selector control valve 14 is shifted toposition 92 in which it allows pump flow to be communicated to motor 15via the conduit 17 and to the counter-balance valve 93 via the conduit94.

The orifice choke 96 modulates pilot flow to the counter-balance valve93 and prevents over sensitive operation thereof. When the pilotpressure reaches the range of 300-500 psi, the valve 93 will shift to anopen position in which is allowed communication between the motor ports102 and the tank 11 via conduits the 97,98,99,16 and 18. Thecounter-balance valve 93 maintains a minimum back pressure range of300-500 psi in the motor which pressure assures the release of the brakeprior to the lowering of the boom and prevents cavitation in the motor15.

The two-way relief valve 100 protects the motor circuitry by directingflow back to the motor inlet via the conduits 101 and 17 at such timesthat the load is excessive and back pressure in the motor reaches the3,000 psilevel. This provision also reduces cavitation in the motor bysupplying make-up fluid to the inlet ports when the load becomesexcessive.

Shifting of the selector control valve 14 to position 90 places thecircuit in a boom raise mode. In this condition, flow from pump 10 iscommunicated through conduits 13 and 16 to motor 15. Conduit 26 alsocommunicates the pressurized pump flow to the brake 25 for the releasethereof. The two-way relief valve 100 establishes maximum motor pressureat 3,000 psi and relieves the system by communicating relief flow to thetank 11 via the conduits 101 and 17. Relief valve 106 protects the pump10 from excessive pressure by communicating conduit 13 with conduit 18and with tank 11.

Check valves 104 and 105 are provided to block flow in thedirection'indicated and to maintain fluid in the respective associatedconduits and also to block flow to the motor 15 until after the brakespring force is overcome by pressurized fluid and the brake is released.The Counterweight System The lateral position of the counterweights (notshown) relative to the tractor is hydraulically controlled by a threeposition valve 27 similar to valve 14. Two hydraulic cylinders 28, 29are arranged to move the counterweights transversely of the tractorcentreline by means of hydraulic fluid supplied through line 30 from thesmall section of a double hydraulic pump 31 of the fixed displacementtype drawing hydraulic fluid through a suction filter 83 from thereservoir 11.

When the valve 27 is in the central neutral position as depicted, thesupply of hydraulic fluid is straight through is straight through theopen-centre of valve 27 into line 36 connected to the hoist system whichis described later. If the valve 27 is displaced into either a second orthird position, then hydraulic fluid is supplied to one end of thehydraulic cylinders 28, 29

through one of lines 32, 33 and displaced hydraulic fluid flows out ofthe other end of the hydraulic cylinders 28, 29 through the other one oflines 32, 33. A counterbalance valve arrangement 34 is provided in line33. A pressure relief valve 35 is associated with valve 27 and isconnected to line 36.

The Hoist System The supply of hydraulic fluid to the hoist system isderived from the large section of the double hydraulic pump 31.Hydraulic fluid in output line 37 is directed through line 39 to athree-position valve 38, through line 40 to a two-position valve 41 withthe output line 37 including a bypass filter 42.

The valve 38 is for controlling a two speed hydraulic motor 43 of thekind specified. Valve 38 is substantially the same as the other threeposition valves 27 and 14, except that it includes a restrictor 44 whichserves to throttle flow to the reservoir 11 through line 45 when thevalve 38 is in its second or third position.

The valve 41 is provided for operating the valve 46 of the hydraulicmotor 43 that controls, in known manner, the speed of the motor. Thevalve 41 is connected to a line 47 leading to the reservoir 11, and ineither operative position provides a through passage for hydrau- Iicfluid to the brake cylinder 48 of the spring-operated band'type winchbrake (not shown) that is held off by the brake cylinder 48.

With reference to the operation of the brake cylinder 48, when the valve38 is in the neutral position depicted in the drawing there is nohydraulic fluid supplied to the brake cylinder 48'and the brake is inthe applied position. The hydraulic fluid in line 39 flows through theopen centre of valve 38 to the reservoir 11 via return line 45. Thebrake cylinder line 52 is also open to the reservoir 11 through shuttlevalve 51, line 54 through shuttle valve 50, and the line 49, valve 41 toline 40 and thence to the reservoir 11 through opencentred valve 38.

When the valve 38 is in either its second or third positions, that iswhen the hydraulic motor 43 is being driven, hydraulic fluid is suppliedto the brake cylinder 48 to hold the winch brake in the off" position.When the motor speed control valve 41 is in the position depicted,hydraulic fluid flows through line 40 through port p to port a of valve41. Flow is then through line 49, through shuttle valve 50 into line 54to actuate shuttle valve 51 and into the brake line 52. The actuation ofthe shuttle valve 51 prevents the return flow of hydraulic fluid to thereservoir 11 through line 57. When the motor speed control valve 41 isin its other position, the hydraulic fluid flows through line 40,through port p to port b of valve 41, through line 53 to actuate shuttlevalve 50 to close line 60. The flow is then to the brake line 52 throughline 54 and shuttle valve 51 which is actuated in the same way as justdescribed.

As will be appreciated, when there is a reduction in hydraulic pressurein the brake line 52, the winch brake will be applied. Such reduction inhydraulic pressure will occur when valve 38 is moved to the neutralposition, or if a supply line fails, or under other circumstances whichwill be explained later in connection with the system for operating thehoist winch with free fall of the load.

The speed of the hydraulic 43 is controlled in known manner by theactuation of spool valve 46 to which hydraulic fluid is supplied throughline when the conis either through line 58,-or through line 59dependingon the position of valve 38. The return'flow of hydraulic fluidfrom the motor 43 is through either line 59 or 58. There is alsoprovided an arrangement of valves to maintain a predetermined pressureacting on the motor pistons. This arrangement includes a non-returnpressure limiting circuit 78 and a counter-balance valve 79. From thisarrangement of valves the hydraulic fluid returns through the valve 38,restrictor 44 to the line 45 leading to the reservoir 11.

The crux of this invention is that the hydraulic motor 43 can beoperated so that free fall of the hoist load can be obtained,andcontrolled without risk of damage to the motor 43. This operation andcontrol will now be explained having regard to the foregoing descriptionand explanation. a

The free-fall hydraulic system associated with control valve 56 isarranged so that it can only be effective I when the hoist control valve38 is in the neutral central position, that is when the hydraulic motoris not being driven, such as when a load is suspended on the hoist inmid-air.- This is done by providing a drain valve 64 which ismechanically coupled by a suitable linkage to the operating linkage ofvalve 38. When valve 38 is in either its second or third position, theline 66 leading to valve 64 is open to the reservoir 11' through drainline 65 and. thus pressure cannot be developed in line 67 which is inthe free fall system. Accordingly, free fall of the load can only beobtained when the hoist valve 38 and drain'valve 64 are in the operativepositions depicted in the accompanying drawing; 1

The free fall of the hoist load is controlled by the control valve 56 towhich hydraulic fluid flows from the control valve 27 of thecounterweight system, through line 36 including by -pass filter 61. Thefree fall control valve 56 is depicted in the inoperative positionwhereby the brake line 52 is open to the reservoir 11, flow beingthrough line 55, line '62 including restrictor 63, through port B toport T of the valve 56 to' the reservoir return line 57. The hydraulicfluid flows through port P to port Aof valve 56, through line'68 to anon-return valve 69 in'line 70, to a line 71 and thus to anopenreservoir 72 to which flow is controlled by a non-return valve 73 havinga predetermined opening pressure. The line 71 also includes a pressurerelief valve 74 for relieving the pressure in line 36, but under normalconditions as now being described, this relief valve 74 merely acts as anon-return valve in line 71.

,The open reservoir 72 which may be integral with reservoir 11, is alsoconnected to the motor casing bycylinder 48. Hydraulic fluid also flowsfrom the line 62 to line 67 connected to a pair of spool valves 76, 77,

which are thus actuated. The lower hydraulic pressure which is presentin the idle hydraulic motor 43 and which is determined by the valves 78,79 is vented to an open reservoir through the valves 76, 77 on theiractuation, and thus the pressure maintained in the motor casing by thevalve 73 is greater than that in the motor cylinder bores and thepistons are displaced radially inwards by the hydraulic pressure in themotor casing so that the driving means as aforedescribed is moved out ofengagement with the cam ring.

Accordingly, as the spool valves 76, 77 are merely operated by arelatively low pilot pressure, and the brake cylinder 48 hasa muchhigher actuation pressure,-the brake is released slightly after themotor pistons have been displaced.

in practice, we have found that if the motor cylinder bore pressure canbe reduced to a very low figure. then a'motor casing pressure of from 22p.s.i. to 36 psi. is sufficient in a hydraulic motor of the kindspecified developing a maximum torque of 545 ft. lbs, per psi.

To stop the free fall of the load, the free fall control valve 56 isreturned into the position as depicted in the drawing. However, nowthere is no hydraulic pressure in the motor supply and discharge lines59, 58. A positive pressure, greater than the motor casing pressure hasto be developed quickly to render the motor 43 operative again foroperating the hoist winch. This development of operative hydraulicpressure in themotor 43 to displace the pistons radially outwards tore-engage the driving meanswith the cam ring is achieved when the freefall control valve 56 is returned to position depicted in the drawing.When valve 56 is in' this position hydraulic fluid from line 36 flowingnow through line 68 can overcome the two non-return valves 80, 81 inline 82 connected to motor lines'58, 59. The operating opening pressuresof these valves 80, 81- are set lower than the non-return valve 69, thusthe minimum operating pressure determined by the arrangement of valves78 and 79 is quickly restored. Hydraulic fluid also flows to thereservoir ll from the brake line 52, through shuttle 'valve 51 throughline 55,-through the restrictor 63 in'line 62, and through valve 56 toline 57. This exhausts the brake cylinder 48 which'is releasedand thebrake is applied. The spool valves 76 and 77 are also released again bythe pressure drop in line 67, buta throttle non-return valve 84 in line67 the restrictor 63 provides a restriction which delays the release ofthe spool valves 76, 77 for a short time to ensure that the brake isapplied slightly before the motor pistons are displaced outwards tore-engage the driving means. The hoist winch is then ready for operationunder the control of valve 38.

It will be appreciated that the opening and limiting pressures arecalculated in relation to a specific application with a particular motorand pump capacity, and without detracting from the scope of thisinvention, a modified form of hydraulic circuit as just described couldbe employed to achieve the same result. However, in this embodiment ofthe invention simple operation and control is achieved. and otheradvantages are obtained.

it should be noted that the three-position valves I4. 27 and 38 are ofthe open-centre kind so that when any of these valves are maintained inthe neutral position. such as when the tractor is idling, thehydraulictluid is returned directly to the reservoir 11] without passingthrough the associated hydraulic circuits. This arrangement is mostadvantageous because excessive heating of the hydraulic fluid isprevented and the provision of additional oil coolers can be avoided.

The actuation of the hoist-winch brake is synchronised with thereadiness of the hydraulic motor, and this provides a fail-safe feature.Additionally, the coupling of the drain valve 164 to the hoist winchmotor control valve 138 provides another fail-safe feature. Each of themanually operable control valves are of the dead-man type biased toreturn to the neutral position,

Additionally, if'there should be a failure in the hydraulic fluid supplyto the hoist winch motor 143 it is still possible to operate the freefall to release, for instance a suspended load. This is because thehydraulic fluid supply to actuate the free fall sub-system is taken fromthe counterweight system With this invented system a luffing crane canbe controlled and operated completely by a hydraulic system embodyinghydraulic motors of the kind specified. This reduces the overallcomplexity and weight of hydraulic/mechanical arrangements.

Although the preferred embodiment of this invention as just described isdirected to operating and controlling the winches and counterweights ofpipe-laying apparatus adapted for attachment to a tractor, it will beappreciated by those familiar with hydraulic engineering that thisinvention may be embodied in the original equipment of the tractor orembodied in other apparatus such as simple lifting hoists, jib cranes,and winches for trawling or dredging by appropriately modifying thehydraulic systems.

Weclaim: A v 1. In a system for'operating and controlling a winding geardriven by a rotary hydraulic motor of the kind including a first memberhaving a plurality of radial bores, a motor element displaceable in eachof the bores and each having an associated driving means, a cam ringhaving cam faces engaged by the driving means and means for selectivelysupplying hydraulic fluid to the bores to displace the motor elementsradially in a predetermined sequence and by pressure-engagement of thedriving means with the cam faces to produce relative rotation betweenthe cam ring and said first member, the system includingpump means forsupplying hydraulic fluid to the hydraulic motor, normally applied brakemeans for said winding gear, fluid pressure means including fluidcommunication means for releasing said brake means, the improvementcomprising; free-run means including fluid communication means forapplying to the motor elements of the hydraulic motor a hydraulicpressure differential to displace the motor elements radially inwardlyand withdraw the associated driving means from contact with the camfaces of the cam ring whereby the cam ring can rotate freely, saidfree-run means including means for preventing said fluid pressure meansfrom releasing said brake means until said pressure differential hasbeen developed to condition said motor elements and associated drivingmeans to move radially inwardly away from contact with said cam faces ofsaid cam ring, the hydraulic pressure for the free-run means beingderived from a source separate from the pump means supplying the motor.

2. The invention of claim 1 including a casing for said hydraulic motorand means for applying, on actuation of the free-run means, a hydraulicpressure inthe interior of said casing of the motor higher than thatobtain ing in said bores.

3. The invention of claim 1 including means for re ducing, on actuationof the free-run means, standing hydraulic pressure in said bores.

4. The invention of claim 2 further including valve means for actuatingthe free-run means.

5. The invention of claim 4 including a casing for said hydraulic motorand wherein said valve means are adapted, on actuation. to connect asource of hydraulic pressure to the interior of said casing.

l 6. The invention-of claim 5 further including means for maintaining astanding pressure in the bores when the motor is idle and wherein saidvalve means, on actuation, operate means for releasing saidstandingpressure from the bores of the motor.

7, In a system for operating and controlling a winding gear driven by arotary hydraulic motor of the kind including a first member having aplurality of radial bores, a motor element displaceable in each of thebores and each having an associated driving means, a cam. ring havingcam faces engaged by the driving means and means for selectivelysupplying hydraulic fluid to the bores todisplace the motor elementsradially in a predetermined sequence and by pressure engagement of thedriving means with the cam faces to produce relative rotation betweenthe cam ring and said first member, .the system including pump meansfor-supplying hydraulic fluid to 'the hydraulic motor.

rotate freely; said free-run meansincluding means for preventingsaidfluid pressure means from releasing said brake'means until saidpressuredifferential has been developed to condition said motor elementsand associated driving means to move radially'inwardlyv away fromcontact with said cam faces of'said cam ring, valve means forac'tuatingthe free-run means, a casing for hydraulic motor and wherein said'valvemeans are adapted, on actuating, to connect a source of hydraulicpressure to the interior of said casing, means for maintaining astanding pressure in the bores when the motor is idle and wherein saidvalve means, on actuation, operate means for releasing said standingpressure from the bores of the motor, said valve means, on restorationto its normal position after actuation, acting to connect a source ofhydraulic pressure to the bores of the motor to restore the standingpressure. I

8. The invention of claim 7 wherein said valve means. on restoration ofits normal position after actuation. connect a source of hydraulicpressure to the bores of the motor to restore the standing pressure,said means for preventing brake means release being also provided forensuring that the brake means is applied before the standing pressure isrestored. I

9. in a system for operating and controlling a winding gear driven by areversible rotary hydraulic motor, driving means for selectivelysupplying hydraulic fluid to said rotary hydraulic motor to rotate saidhydraulic motor and said winding gear, said driving means includingfirst supply means for supplying hydraulic pressure fluid to saidhydraulic motor, normally applied brake means for said winding gear,fluid pressure means including fluid communication means for releasingsaid brake means, free-run means including fluid communication means forapplying to a portion of the hydraulic motor a hydraulic pressure toallow said hydraulic motor to rotate freely without load, said free-runmeans including second supply means for supplying said hydraulic motorportion, said second supply means including a source of hydraulic fluidseparate from the source of hydraulic fluid for said drive means, saidfreerun means including means for preventing said fluid pressure meansfrom releasing said brake means until said hydraulic pressure has beensupplied to said portion of said motor to condition said motor to rotatefreely without load, said driving means for said reversible rotaryhydraulic motor further including a motor control valve for controllingflow of hydraulic fluid to said hydraulic motor for driving rotationthereof, said control valve having a first portion for supplying fluidto cause said motor to rotate in a first direction, a secondposition'for supplying fluid to cause said motor to rotate in thereverse direction, and a neutral position in which fluid flow to andfrom said hydraulic motor is blocked and a hydraulic fluid lock iscreated which retards rotation of said hydraulic motor in either of saidfirst or reverse directions, said free-run means further including asecondary valve means separate from said motor control valve forcontrolling the supply of hydraulic fluid pressure to said motorportion.

10. in a system for operating and controlling a winding gear driven by arotary hydraulic motor, driving means for selectively supplyinghydraulic fluid to said rotary hydraulic motor to rotate said hydraulicmotor and said winding gear, said driving means including first supplymeans for supplying hydraulic. pressure fluid to said hydraulic motor,normally applied brake means'for said winding gear, fluid pressure meansincluding fluid communication means for releasing said brake means,free-run means including fluid communication rneans for applying to aportion of the hydraulic motor a hydraulic pressure to allow saidhydraulic motor to rotate freely without load, said free-run meansincluding second supply means for supplying said hydraulic motorportion, said second supply means including a sourceof hydraulic fluidseparate from the source of hydraulic fluidfor said drive means, saidfreerun means including means for preventing said fluid pressure meansfrom releasing said brake means until said hydraulic pressure has beensupplied to said portion of said motor to condition said motor to rotatefreely without load, said free-run means further including tertiaryvalve means for preventing said rotary hydraulic motor from returningfrom the freely rotating condition to the driving condition prior to thereapplication of said brake means.

11. in a system for operating and controlling a winding gear driven by arotary hydraulic motor of the kind including a first member having aplurality of radial bores, 21 motor element displaceable in each of thebores and each having an associated driving means, a cam ring having cuml'aces engaged by the driving means and means for selectively supplyinghydraulic fluid to the bores to displace the motor elements radially ina predetermined sequence and by pressure engagement of the driving meanswith the cam faces to produce relative rotation between the cam ring andsaid first member, the system including pump means for supplyinghydraulic fluid to the hydraulic motor, normally applied brake means forsaid winding gear, fluid pressure means including fluid communicationmeans for releasing said brake means, the improvement comprising;free-run means including fluid communication means for applying to themotor elements of the hydraulic motor a hydraulic pressure differentialto displace the motor elements radially inwardly and withdraw theassociated driving means from contact with the cam faces of the cam ringwhereby the cam ring can rotate freely, said free-run means includingmeans for preventing said fluid pressure means from releasing said brakemeans until said pressure differential has been developed to conditionsaid motor elements and associated driving means to move radiallyinwardly away from contact with said cam faces of said cam ring, anoperators control for the motor wherein the freerun means includes meanscoupled to the operator's motor control for ensuring that the free-runmeans can only be actuated when the motor control is in the offposition.

12. In a system for operating and controlling a winding gear driven by arotary hydraulic motor, driving means for selectively supplyinghydraulic fluid to said rotary hydraulic motor to rotate said hydraulicmotor and said winding gear, said driving means including first supplymeans for supplying hydraulic pressure fluid to said hydraulic motor,normally applied brake means for said winding gear, fluid pressure meansincluding fluidcommunication means for releasing said brake means,free-run means including fluid communication means for applying to aportion of the hydraulic motor a hydraulic pressure to allow saidhydraulic motor. to rotate freely without load. said free-run meansincluding second supply means for supplying said hydraulic motorportion, said second supply means including a source of hydraulic fluidseparate from the source of hydraulic fluid for said drive means, saidfreerun means including means for preventing said fluid pressure meansfrom releasing said brake means until said hydraulic pressure has beensupplied to said portion of said motor to condition said motor to rotatefreely without load.

13. The invention of claim 12 wherein said rotary hydraulic motor isreversible and said hydraulic motor drive means further includes a motorcontrol valve for controlling flow of hydraulic fluid to said hydraulicmotor for driving rotation thereof, said control valve having a firstposition for supplying fluid to cause said motor to rotate in a firstdirection, a second position for supplying fluid to cause said motor torotate in the reverse direction, and a neutral position in which fluidflow to and from said hydraulic motor is blocked and a hydraulic fluidlock is created which retards rotation of said hydraulic motor in eitherof said first or reverse directions.

a k a: k a

V UNITED STATES PATErg r OFFICE A 6 CERTIFICATE OF CCRRECTECN Patent No.3,815,?8 Dated June 11, 97

Inyentofls) EVALD G. AXELSSON et 8.1

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

lnF ig. 3 of the drawing, numerals 90, 91, 92, 93, 94, 96, 97, 98, 99',100', 101, 102, 103, 10M, 1o5 and 106 are added along with lead lineswhere indicated;

In Fig. 4 of the drawing,'letters A; B, a, b,

P, p and T are added along with lead lines where indicated.

Column 10, line 3, change "1" to --2-- Column 10, line 6, change "2" to---l--.

Signed and sealed thi-a 5th day of November. 1974.,

(SEAL) Attest:

McCOY M, GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents UGCOMWDC 603764 69 -'ORM P0405) (IO-69) f" i an covmmuzm mum-covnc: 1 Inc o-su-uc

1. In a system for operating and controlling a winding gear driven by arotary hydraulic motor of the kind including a first member having aplurality of radial bores, a motor element displaceable in each of thebores and each having an associated driving means, a cam ring having camfaces engaged by the driving means and means for selectively supplyinghydraulic fluid to the bores to displace the motor elements radially ina predetermined sequence and by pressure engagement of the driving meanswith the cam faces to produce relative rotation between the cam ring andsaid first member, the system including pump means for supplyinghydraulic fluid to the hydraulic motor, normally applied brake means forsaid winding gear, fluid pressure means including fluid communicationmeans for releasing said brake means, the improvement comprising;free-run means including fluid communication means for applying to themotor elements of the hydraulic motor a hydraulic pressure differentialto displace the motor elements radially inwardly and withdraw theassociated driving means from contact with the cam faces of the cam ringwhereby the cam ring can rotate freely, said free-run means includingmeans for preventing said fluid pressure means from releasing said brakemeans until said pressure differential has been developed to conditionsaid motor elements and associated driving means to move radiallyinwardly away from contact with said cam faces of said cam ring, thehydraulic pressure for the free-run means being derived from a sourceseparate from the pump means supplying the motor.
 2. The invention ofclaim 1 including a casing for said hydraulic motor and means forapplying, on actuation of the free-run means, a hydraulic pressure inthe interior of said casing of the motor higher than that obtaining insaid bores.
 3. The invention of claim 1 including means for reducing, onactuation of the free-run means, standing hydraulic pressure in saidbores.
 4. The invention of claim 2 further including valve means foractuating the free-run means.
 5. The invention of claim 4 including acasing for said hydraulic motor and wherein said valve means areadapted, on actuation, to connect a source of hydraulic pressure to theinterior of said casing.
 6. The invention of claim 5 further includingmeans for maintaining a standing pressure in the bores when the motor isidle and wherein said valve means, on actuation, operate means forreleasing said standing pressure from the bores of the motor.
 7. In asystem for operating and controlling a winding gear driven by a rotaryhydraulic motor of the kind including a first member having a pluralityof radial bores, a motor element displaceable in each of the bores andeach having an associated driving means, a cam ring having cam facesengaged by the driving means and means for selectively supplyinghydraulic fluid to the bores to displace the motor elements radially ina predetermined sequence and by pressure engagement of the driving meanswith the cam faces to produce relative rotation between the cam ring andsaid first member, the system including pump means for supplyinghydraulic fluid to the hydraulic motor, normally applied brake means forsaid winding gear, fluid pressure means including fluid communicationmeans for releasing said brake means, the improvement comprising;free-run means including fluid communication means for applying to themotor elements of the hydraulic motor a hydraulic pressure differentialto displace the motor elements radially inwardly and withdraw theassociated driving means from contact with the cam faces of the cam ringwhereby the cam ring can rotate freely, said free-run means includingmeans for preventing said fluid pressure means from releasing said brakemeans until said pressure differential has been developed to conditionsaid motor elements and associated driving means to move radiallyinwardly away from contact with said cam faces of said cam ring, valvemeans for actuating the free-run means, a casing for hydraulic motor andwherein said valve means are adapted, on actuating, to connect a sourceof hydraulic pressure to the interior of said casing, means formaintaining a standing pressure in the bores when the motor is idle andwherein said valve means, on actuation, operate means for releasing saidstanding pressure from the bores of the motor, said valve means, onrestoration to its normal position after actuation, acting to connect asource of hydraulic pressure to the bores of the motor to restore thestanding pressure.
 8. The invention of claim 7 wherein said valve means,on restoration of its normal position after actuation, connect a sourceof hydraulic pressure to the bores of the motor to restore the standingpressure, said means for preventing brake means release being alsoprovided for ensuring that the brake means is applied before thestanding pressure is restored.
 9. In a system for operating andcontrolling a winding gear driven by a reversible rotary hydraulicmotor, driving means for selectively supplying hydraulic fluid to saidrotary hydraulic motor to rotate said hydraulic motor and said windinggear, said driving means including first supply means for supplyinghydraulic pressure fluid to said hydraulic motor, normally applied brakemeans for said winding gear, fluid pressure means including fluidcommunication means for releasing said brake means, free-run meansincluding fluid communication means foR applying to a portion of thehydraulic motor a hydraulic pressure to allow said hydraulic motor torotate freely without load, said free-run means including second supplymeans for supplying said hydraulic motor portion, said second supplymeans including a source of hydraulic fluid separate from the source ofhydraulic fluid for said drive means, said free-run means includingmeans for preventing said fluid pressure means from releasing said brakemeans until said hydraulic pressure has been supplied to said portion ofsaid motor to condition said motor to rotate freely without load, saiddriving means for said reversible rotary hydraulic motor furtherincluding a motor control valve for controlling flow of hydraulic fluidto said hydraulic motor for driving rotation thereof, said control valvehaving a first portion for supplying fluid to cause said motor to rotatein a first direction, a second position for supplying fluid to causesaid motor to rotate in the reverse direction, and a neutral position inwhich fluid flow to and from said hydraulic motor is blocked and ahydraulic fluid lock is created which retards rotation of said hydraulicmotor in either of said first or reverse directions, said free-run meansfurther including a secondary valve means separate from said motorcontrol valve for controlling the supply of hydraulic fluid pressure tosaid motor portion.
 10. In a system for operating and controlling awinding gear driven by a rotary hydraulic motor, driving means forselectively supplying hydraulic fluid to said rotary hydraulic motor torotate said hydraulic motor and said winding gear, said driving meansincluding first supply means for supplying hydraulic pressure fluid tosaid hydraulic motor, normally applied brake means for said windinggear, fluid pressure means including fluid communication means forreleasing said brake means, free-run means including fluid communicationmeans for applying to a portion of the hydraulic motor a hydraulicpressure to allow said hydraulic motor to rotate freely without load,said free-run means including second supply means for supplying saidhydraulic motor portion, said second supply means including a source ofhydraulic fluid separate from the source of hydraulic fluid for saiddrive means, said free-run means including means for preventing saidfluid pressure means from releasing said brake means until saidhydraulic pressure has been supplied to said portion of said motor tocondition said motor to rotate freely without load, said free-run meansfurther including tertiary valve means for preventing said rotaryhydraulic motor from returning from the freely rotating condition to thedriving condition prior to the re-application of said brake means. 11.In a system for operating and controlling a winding gear driven by arotary hydraulic motor of the kind including a first member having aplurality of radial bores, a motor element displaceable in each of thebores and each having an associated driving means, a cam ring having camfaces engaged by the driving means and means for selectively supplyinghydraulic fluid to the bores to displace the motor elements radially ina predetermined sequence and by pressure engagement of the driving meanswith the cam faces to produce relative rotation between the cam ring andsaid first member, the system including pump means for supplyinghydraulic fluid to the hydraulic motor, normally applied brake means forsaid winding gear, fluid pressure means including fluid communicationmeans for releasing said brake means, the improvement comprising;free-run means including fluid communication means for applying to themotor elements of the hydraulic motor a hydraulic pressure differentialto displace the motor elements radially inwardly and withdraw theassociated driving means from contact with the cam faces of the cam ringwhereby the cam ring can rotate freely, said free-run means includingmeans for preventing said fluid pressure means from releasing said brakemeans until said pressure differential has been developed to conditionsaid motor elements and associated driving means to move radiallyinwardly away from contact with said cam faces of said cam ring, anoperator''s control for the motor wherein the free-run means includesmeans coupled to the operator''s motor control for ensuring that thefree-run means can only be actuated when the motor control is in the offposition.
 12. In a system for operating and controlling a winding geardriven by a rotary hydraulic motor, driving means for selectivelysupplying hydraulic fluid to said rotary hydraulic motor to rotate saidhydraulic motor and said winding gear, said driving means includingfirst supply means for supplying hydraulic pressure fluid to saidhydraulic motor, normally applied brake means for said winding gear,fluid pressure means including fluid communication means for releasingsaid brake means, free-run means including fluid communication means forapplying to a portion of the hydraulic motor a hydraulic pressure toallow said hydraulic motor to rotate freely without load, said free-runmeans including second supply means for supplying said hydraulic motorportion, said second supply means including a source of hydraulic fluidseparate from the source of hydraulic fluid for said drive means, saidfree-run means including means for preventing said fluid pressure meansfrom releasing said brake means until said hydraulic pressure has beensupplied to said portion of said motor to condition said motor to rotatefreely without load.
 13. The invention of claim 12 wherein said rotaryhydraulic motor is reversible and said hydraulic motor drive meansfurther includes a motor control valve for controlling flow of hydraulicfluid to said hydraulic motor for driving rotation thereof, said controlvalve having a first position for supplying fluid to cause said motor torotate in a first direction, a second position for supplying fluid tocause said motor to rotate in the reverse direction, and a neutralposition in which fluid flow to and from said hydraulic motor is blockedand a hydraulic fluid lock is created which retards rotation of saidhydraulic motor in either of said first or reverse directions.